I think it is a bug introduced by a CS3 auto update recently. I wish there was a way of rolling back the updates…. Anyone from Adobe around??
Meanwhile, here is your workaround;
When exporting movie (24 or 25f, out of Canon XH….), in settings, under “Keyframe and Rendering”, tick the box beside “Deinterlace video footage”…….
Selecting “No Fields (Progressive Scan)” does not work…..BUG!!!